Respiratory

Question 1

What is external respiration?

Answer 1

The sequence of events that lead to the exchange of carbon dioxide and oxygen between the external environment and the cells of the body

Question 2

What are the 4 steps of external respiration?

Answer 2

1/ Ventilation/gas exchange between the atmosphere and the alveoli 2/ Exchange of oxygen and carbon dioxide between the alveoli and the blood. 3/ transport of oxygen and carbon dioxide between the lungs and tissues 4 exchange of carbon dioxide and oxygen between the blood and tissues

Question 3

What is Boyles Law

Answer 3

At any constant temperature, the pressure exerted by a gas varies inversely with the volume of the gas

Question 4

What 3 pressures are important in ventilation?

Answer 4

Atmospheric. Intra-alveolar. Interpleural

Question 5

What gives the lungs recoil during expiration? Which is more important?

Answer 5

Elastic connective tissue. Alveolar surface tension - more important

Question 6

What is intracellular fluid cohesiveness?

Answer 6

The attraction of water molecules for each other in the intrapleural fluid. This causes resistance to then being pulled apart

Question 7

What is the negative intrapleural pressure?

Answer 7

the sub atmospheric intracellular pressure creates a transmural pressure gradient across the lung wall and across the chest wall. Causes lungs to expand outwards while the chest is forces to squeeze inwards.

Question 8

What three pressures are important in ventilation?

Answer 8

Atmospheric pressure, intra-alveolar pressure and intrapleural pressure

Question 9

what happens to the ribs when the external intercostal muscles contract?

Answer 9

The ribs lift and the sternum moves out - bucket handle mechanism

Question 10

Is inspiration an active or passive process?

Answer 10

Active

Question 11

Is normal expiration a passive or active process?

Answer 11

Passive - brought by relaxation of inspiratory muscles

Question 12

what is La Place’s Law

Answer 12

The inward directed collapsing pressure is proportional to the surface tension and inversely proportional to the radius

Question 13

What is the function of type 2 pneumocytes?

Answer 13

surfactant production

Question 14

What is alveolar interdependence and what does it do?

Answer 14

Helps keep alveoli open. If an alveolus starts to collapse, the site surrounding alveoli are stretched and then recoil exerting expanding forces in the collapsing alveolus to open it.

Question 15

Name the 3 forces keeping alveoli open?

Answer 15

Transmural pressure gradient. Pulmonary surfactant ( opposes surface tension). alveolar interdependence.

Question 16

Name the 2 forces promoting alveolar collapse?

Answer 16

elasticity of stretched pulmonary connective tissue fibres. Alveolar surface tension.

Question 17

What is FVC?

Answer 17

the maximum volume that can be forcibly expelled from the lungs following a maximum inspiration.

Question 18

In obstructive disease, the FEV1, FVC and FEV1/FVC ratio are generally what, compared to normal lungs?

Answer 18

FEV1 - reduced. FVC- normal. Think obstructive : something stopping air coming out as quickly. Ratio is lower

Question 19

In restrictive disease, the FEV1, FVC and FEV1/FVC ratio are generally what, compared to normal lungs?

Answer 19

FEV1 and FVC reduced. Think restrictive : something stopping lungs filling. Less volume in lungs means less can come out as quickly. Ratio is normal as both are reduced.

Question 20

What is the primary determinant of airway resistance?

Answer 20

Radius of conducting airways

Question 21

During inspiration, intrapleural pressure increase/decreases?

Answer 21

Decreases - as lungs fill, pressure gradient falls.

Question 22

During expiration, intrapleural pressure increase/decreases?

Answer 22

Increases - pressure gradient forces air out of lungs

Question 23

pulmonary compliance

Answer 23

The measure of effort that has to go into stretching pr distending the lungs. The less compliant the more work requires to produce a given degree of inflation.

Question 24

What disease state/s is/are there decreased compliance?

Answer 24

pulmonary fibrosis/oedema/ pneumothorax, pneumonia, absence of surfactant

Question 25

What disease state/s is/are there increased compliance?

Answer 25

Emphysema. Leads to hyperinflation of lungs.

Question 26

what is anatomical dead space?

Answer 26

Area in the lungs where the is no gas exchange

Question 27

Pulmonary ventilation is…?

Answer 27

the volume of air breathed in and out per minute

Question 28

Alveolar ventilation is…?

Answer 28

the volume of air exchanged between the atmosphere and alveoli per min.

Question 29

Ventilation is…?

Answer 29

The rate at which has is passing through the lungs

Question 30

Perfusion is…?

Answer 30

The rate at which blood is passing through the lungs

Question 31

What is alveolar dead space?

Answer 31

ventilated alveoli which is not adequately perfused with blood

Question 32

Four factors that influence rate of gas exchange…

Answer 32

partial pressure gradient of oxygen and carbon dioxide. Diffusion coefficient for oxygen and carbon dioxide, surface area of alveolar membrane. Thickness of alveolar membrane.

Question 33

what is Dalton’s Law?

Answer 33

The total pressure in a system is the sum of the partial pressures of each individual component in the gas mixture.